resumo
The structural organization and the transformation mechanism of the layered carbon phase produced from the tetragonal and rhombohedral variants of the 2D polymers of C-60 were investigated. High Resolution Transmission Electron Microscopy imaging combined with Electron Diffraction analysis were performed for samples synthesized at 2.6, 5.0 and 8.5 GPa and 1100 K. The structure of this layered carbon phase is composed of corrugated layers in a pseudo-epitaxial relationship with the {1 1 1}(cubic) planes of the parent polymer phase. A pseudo-martensitic transformation mechanism is proposed with a partial C-C bond reconstruction, as indicated by measurements of the angles between textured 001 reflections. The distribution of dense polymeric planes in tetragonal, rhombohedral and distorted pseudo-cubic 2D polymers as well as the crystallographic relationships between different layered carbon microstructures indicate that the carbon layers are generated from the polymerized dense planes of each structure. (C) 2012 Elsevier Ltd. All rights reserved.
palavras-chave
HIGH-PRESSURE; FULLERITE C-60; ELECTRON-DIFFRACTION; THIN-FILMS; PHASES; SUPERHARD; GRAPHITE; DIAMOND; POLYMERIZATION; TRANSFORMATION
categoria
Chemistry; Materials Science
autores
Lepoittevin, C; Alvarez-Murga, M; Marques, L; Mezouar, M; Hodeau, JL
nossos autores
agradecimentos
C. Lepoittevin thanks Dr. P. Bayle-Guillemaud from the Commissariat d'Energie Atomique (CEA) Grenoble for the access of the JEOL 4000EX microscope. The European Synchrotron Radiation Facility is acknowledged for provision of synchrotron radiation beamtime for the in-situ sample characterization. M. Alvarez-Murga acknowledges CONACYT Grant 211996. L. Marques acknowledges 'Fundacao para a Ciencia e Tecnologia', Lisbon (Project No. PTDC/FIS/104310/2008).